Many reports indicate that a majority of patients with schizophrenia have poor insight or lack awareness of illness (LAI). Specifically, such patients deny, fail to acknowledge, or more broadly, lack awareness of having a mental disorder or symptoms of a mental disorder. This important topic has been largely neglected due to the unavailability of psychometrically sound assessment methods. We propose that insight is a multidimensional construct and have developed rating scales that sample discrete and global aspects of LAI across a variety of manifestations of illness. The proposed project will: 1) complete a comparative study of the reliability and validity of several methods of measuring LAI; 2) further investigate the psychometric properties of the Scale to assess Unawareness of Mental Disorder (SUMD); 3 extend previous work examining the prognostic value of subtyping by degree of LAI; and 4) test specific hypotheses regarding the neuropsychological correlates of LAI in schizophrenia. The present study will be conducted at New York State Psychiatric Institute's (NYSPI) Schizophrenia Research Unit, which serves as a collaborative center for schizophrenia research at NYSPI and Columbia University. Previous work has suggested that LAI may have significant predictive power with respect to the long-term course of schizophrenia and may impact on treatment dimensions such as medication compliance. To our knowledge, there have been no studies of the neuropsychology of LAI. Examining the phenomenology of LAI, establishing a psychometrically sound method for its quantification, and examining the neuropsychological correlates are of considerable significance in advancing our understanding of schizophrenia and its treatment.